Voltage varying apparatus for displaying indicia on a cathode ray tube screen



Dec. 29, 1959 AL ETAL 2,919,376

VOLTAGE VARYING APPARATUS FOR DISPLAYING INDICIA ON A CATHODE RAY TUBE SCREEN Filed Oct. 5, 1956 3 Sheets-Sheet l INVENTORS Fen-z L/EWAAD POLF P/GO f/E/NZ KELLER Dec. 29, 1959 F, w p ETAL 2,919,376

VOLTAGE VARYING APPARATUS, FOR DISPLAYING ,INDICIA ON A CATHODE RAY TUBE SCREEN Filed Oct. 5, 1956 5 Sheets-Sheet 2 H INVENTORS' Fm r2 1. u n 41.0 Rou- P GO ////\/Z KELLER 1959 F. LIEWALD ETAL 2,919,376

VOLTAGE VARYING APPARATUS FOR DISPLAYING INDICIA v ON A CATHODE RAY TUBE SCREEN Filed Oct. 5, 1956 a Sheets-$heet a INVENTORS FQ/rz yaw/441v POL: ,Q/eo IVE/NZ K54 45/? United States Patent VOLTAGE VARYING APPARATUS FOR DISPLAY- ING INDICIA ON A CATHODE RAY TUBE SCREEN Fritz Liewald, Berlin-Mahlsdorf, Rolf Rigo, Erfurt/ Thuringia, and Heinz Keller, Berlin, Germany, assignors to VEB Werk fiir Signalund Sicherungstechnik Berlin, Berlin, Germany Application October 5, 1956, Serial No. 614,282 7 4 Claims. (Cl. 3158.6)

My invention relates to apparatus for selectively displaying indicia on a cathode ray tube screen and is directed particularly to apparatus capable of selectively and changeably presenting a numeral or letter or groups of numerals and/ or letters on a cathode ray tube screen for the purpose, for example, of announcing train numbers in railroad protective systems.

The use of photo-cells, appropriately controlle'd inductances, or appropriately magnetized moving wires, bands, disks, etc.', for producing voltage changes for visually presenting letters, numbers or other indicia by electrical means is known. Monoscope tubes or similar discharge tubes in television systems can also be used for remote electrical presentation of visual images. All of these prior devices, however, are complicated, spaceconsuming and expensive to install and operate.

It is accordingly the principal object of my invention to provide a selectively operable indicia displaying device of the character described which has no moving parts, whichv requires few parts and little space, and which is low in energy consumption. ,It is still another object of my invention,to provide an indicia display device of the character described which afiords greater reliability than prior devices and which at the same time requires a minimum of attendance and servicing.

Further objects, advantages and features of the invention will become apparent from the following description when read with reference to the accompanying drawings, wherein:

Fig. l is a perspective View of the voltage varying device according to the invention,

Fig. 2 is an electrical schematic diagram of the improved indicia display system embodying the invention,

Fig. 3 illustrates one form of voltage control mask forming part of the voltage varying device shown in Fig. 1,

Fig. 4 illustrates another form of voltage control mask forming part of the voltage varying device in Fig. l, and

\ impinging upon a corresponding number of receptor electrodes placed behind the mask electrodes. In accordance with a further feature of the invention, the sheetformed electron beam simultaneously scans a plurality of mask-like electrodes located one above the other. The mask electrodes could also be scanned one after another. Furthermore, the electron tube is also provided with one or more control impulse presenting elec- ICE trodes impinged upon by the sheet-like electron beam. In addition, an increase of the intended voltage or current change is possible by the use of one or more auxiliary secondary emission electrodes, or such increase can be eifected by utilizing the mask-like electrodes themselves as secondary emission electrodes. Y

I Referring now to Fig. 1, the sheet-formed electron beam 1 produced by means of the rectangular cathode 7, the controlgrid 8, and the focusing electrodes 9 etfects a voltage drop in the resistor 6 of the output circuit (see Fig. 2) dependent upon the amount .of surface of the anode 3 impinged by the electron beam. If the electron beam 1 is swept back and forth by means of the usual deflection plates 10 and the entire electron beam falls on the anode plate 3, then the voltage drop occurring in the resistor 6 remains constant. Thus, upon reproduction of the character, the velocity of the electron beam deflection in tube 13 adjusts itself to the amount required from time to time 'by the character being presented. The voltage drops occurring in the resistors 6 are conducted to the deflection plates 11 (Fig. 2) of cathode ray tube 13. In order to present the desired characters, such as numbers and letters, upon the phosphorescent screen 12, a voltage drop varying in accordance with the configuration of the character is required. This is eflected in that, due to the back and forth movement of the electron beam 1, it does not always impinge atfull amplitude upon the surface of the anode 3 (Fig. 1) but is controlled in accordance with the shape of the opening of the mask-like electrode 2 to provide a voltage variation corresponding to the configuration of the desired character. If the entire height of the beam is arranged to cooperate with a plurality of anodes 3 masked by respective electrodes 2 disposed one over the other, as shown in Fig. 5, the back and forth movement of the electron beam will thus simultaneously produce in the resistors 6 different variable voltage drops corresponding to their respective mask electrodes 2 so that, through the movement of the electron beam, a plurality of diiferent voltages are produced for simultaneous horizontal and/or vertical deflection. For the purpose of a desired sequence of switching or calculations and the like, one or more of these mask electrodes 2 are constructed as control impulse producing mask electrodes 4, as shown in Fig. 15. In the embodiment of the invention illustrated in Fig. 2, these voltages are controlled together in mutually asymmetrical relation, for reasons of economy; however, they could also be used in symmetrical relation. It is also possible to produce these voltages in a plurality of individual electron tubes, or in a single tube equipped with the corresponding number of anodes and mask electrodes. Auxiliary electrodes 5 and known circuitry as illustrated in Fig. 2 on the one hand minimize space charge and on the other hand permit the use of the desired secondary emission efiect.

By means of corresponding spaced arrangements of the anodes 3 covered by the mask electrodes 2, as illustrated in Figs. 3 and 4, it is also possible to produce, in the output anode current circuit, besides the simultaneous voltage variation described above, voltage varia- I Paitented Dec- 29,. 1 9 59 3 ing with light, devices for presenting pictures for advertising purposes, etc.

It is also to be understood that this disclosure is for the purpose of illustration only and that various omissions, or changes in arrangement of parts, as well, as the substitution of equivalent elements for those herein shown and described, may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

What I claim is:

1. In voltage varying apparatus for displaying symbols on a cathode ray tube screen, the combination comprising an electron tube having a cathode and a plurality of anodes, means providing a sheet-like electron beam between said cathode and said anodes, means for deflectingsaid electron beam across said anodes, a plurality of mask electrodes, one each between said cathode and each of said anodes, said masks each having an opening for the passage of said electron beam, a plurality of output circuits, each interconnecting said cathode with one of said anodes, a load element in each of said output circuits, the widths of the openings in said masks in the direction perpendicular to the direction of beam deflection varying each in accordance with one coordinate of the configuration of a given symbol, so as to correspondingly vary the amount of electrons passing through said masks to said anodes as said beam is deflected, a cathode ray tube having a fluorescent screen and a plurality of beam deflecting members, and circuit means interconnecting one each of said beam deflecting members with one of said load elements, whereby the electron beam of said cathode ray tube will be deflected to trace the configuration of a desired symbol on said screen in accordance with the respective voltage variations in said load elements.

2. The apparatus as defined in claim 1, wherein one of said beam deflecting members is operative to deflect the beam of said cathode ray tube horizontally, and wherein another of said beam deflecting members is operative to deflect the beam of said cathode ray tube vertically.

3. The apparatus as defined in claim 1, including means 4 for rendering one of said mask electrodes operative as a control impulse producing member.

4. Apparatus for producing numbers on a fluorescent screen comprising an electron tube having cathode means and a plurality of anodes in the form of elongated parallel strips, means for projecting an electron beam from said cathode means to said anode, means for deflecting said electron beam along all anodes simultaneously, a plurality of mask electrodes, each interposed between said cathode means and one of said anodes, said mask electrodes being in the form of elongated strips adjacent to and extending along said anodes, said mask electrodes each having an opening for the passage of said electron beams, a plurality of output circuits each connecting said cathode means'and one of said anodes, a load element in each of said output circuits, the width of the openings in said mask electrodes in the direction perpendicular to the direction of beam deflection varying in each mask electrode in accordance with one coordinate of the configuration of a given number, so as to correspondingly vary the amount ofelectrons passing through said mask electrodes to said anodes as said beam is deflected, a cathode ray tube having a fluorescent screen and a plurality of electron beam deflecting plates, circuit means interconnecting one of said deflecting plates with. one of said load elements and another of said deflecting plates with another of said load elements, whereby the electron beam of said cathode ray tube is deflected along the fluorescent screen to trace the configuration of a desired number on said screen in accordance with the respective voltage variations in said load elements.

References Cited in the tile of this patent UNITED STATES PATENTS 2,475,644 Soller July 12, 1949 2,594,731 Connolly Apr. 29, 1952 2,666,162 Holloway Jan. 12, 1954 2,722,623 Law Nov. 1, 1955 2,730,708, McNaney Q Jan. 10, 1956 2,803,769 McNaney Aug. 20, 1957 

